This International Standard specifies requirements for performance, design, materials, testing and inspection, welding, marking, handling, storing and shipping of drill-through equipment used for drilling for oil and gas. It also defines service conditions in terms of pressure, temperature and wellbore fluids for which the equipment will be designed. This International Standard is applicable to and establishes requirements for the following specific equipment: a) ram blowout preventers; b) ram blocks, packers and top seals; c) annular blowout preventers; d) annular packing units; e) hydraulic connectors; f) drilling spools; g) adapters; h) loose connections; i) clamps. Dimensional interchangeability is limited to end and outlet connections. Typical equipment defined by this International Standard is shown in Figures 1 and 2; recommendations for failure reporting are outlined in annex F. This International Standard does not apply to field use or field testing of drill-through equipment.